Adds check for active first-aid during bleed damage

Presumes that during active first-aid operations, the PC is applying pressure or otherwise making some effort not to bleed out, and suppresses bleed damage during the activity.

No string changes or significant feature work, should be able to get in.  Feel free to test it, obviously, but it's working here.

Fixes http://smf.cataclysmdda.com/index.php?topic=5520 .